Here's a secret about me: I like tower defense games. When I'm stressed after a long day of work, watching wave after wave of creeps fall to my expertly designed defenses is just the pick-me-up I need. But tower defense has long been the subject of flash games and RTS mods, and we rarely see a commercial release outside of the iPhone. That's why Sanctum, the new PC tower defense from Coffee Stain Studios, is so interesting to me. I was excited to see a tower defense come out that I was actually willing to spend my hard-earned cash on.

The thin sci-fi story of Sanctum is something that you'll immediately gloss over to get right to the gameplay. You take the role of an engineer whose only task is to prevent an energy core from being attacked by aliens. These aliens have brain functions so limited that all they can do is walk endlessly toward their goal. It's up to you to build the perfect maze, adorned with implements of destruction, in order to defeat them before they reach their goal. There's only one catch. This game is entirely in the first-person perspective.

Sanctum is controlled first-person shooter-style in two phases. The first phase, the building phase, gives you all the time in the world to build your perfect tower maze with whatever resources you have available to you. The second phase, the extermination phase, sends a wave of creeps down your maze. You're even allowed to get in on the fun by blasting them to bits. Enemies will never attack, so, just like any other tower defense game, your only job is to kill them before they reach the end of the maze. If an enemy bumps into you, it will just stun you for a moment and then let you get back to blasting. It's a lot of fun for anyone who gets a kick out of seeing wave after wave of enemies die without resistance.

Enemies in Sanctum have the normal range of tower defense powers for you to deal with. Some can fly right over your maze, while others move extremely fast. Some even have extra armor. However, there are also enemies with FPS-style weaknesses to contend with as well. Some enemies take far more damage from headshots, while others can only be damaged from behind.

To combat this, you have the standard variety of tower defense-type structures. These include the fast but weak tower, the splash damage tower, the anti-air tower, and so forth. You can build them right into your maze, and as you get more resources, you can upgrade those as well. However, you can also spend resources on upgrading one of the three guns your engineer can wield to take on the enemies directly.

The sniper rifle can zoom in on enemies from long ranges and deal massive damage with single shots to their weak points, while the assault rifle lays on thick speedy damage to enemies up close. If you prefer to let your towers do most of the damage, you can also upgrade a freeze gun, which doesn't do as much damage but slows the enemies down. Each gun also has an alternate fire that expands each gun's capabilities. For example, the assault rifle lets you throw grenades, which do splash damage.